CN111258339A - Follow-up control device based on stepping motor and photoelectric switch - Google Patents
Follow-up control device based on stepping motor and photoelectric switch Download PDFInfo
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- CN111258339A CN111258339A CN201911165673.1A CN201911165673A CN111258339A CN 111258339 A CN111258339 A CN 111258339A CN 201911165673 A CN201911165673 A CN 201911165673A CN 111258339 A CN111258339 A CN 111258339A
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Abstract
The invention relates to a follow-up control device based on a stepping motor and a photoelectric switch, wherein the follow-up control device comprises: the FPGA includes: the stepping motor control module is used for converting a motor rotating speed value sent by the DSP into a pulse signal capable of controlling the stepping motor in real time, the rising edge of the pulse signal is effective, and the running step number of the motor is controlled by the number of pulses generated per second; the photoelectric switch signal filtering module is used for filtering input signals of the two photoelectric switches so as to eliminate interference; the angle counting and correcting module accumulates the rotating step number of the stepping motor, accumulates the rotating step number in the forward rotation process, decreases the rotating step number in the reverse rotation process, and corrects the current accumulated step number value through a photoelectric switch signal; after the DSP is electrified, the rotation of the whole motion range is executed, the zero position is searched, and the position of the zero position is recorded; DSPb) generates a speed value of the stepping motor through a PID algorithm according to the current angle value and the target position fed back by the FPGA, and sends the speed value to the FPGA.
Description
Technical Field
The invention relates to a follow-up control device, in particular to a follow-up control device based on a stepping motor and a photoelectric switch.
Background
The closed-loop control technology based on the angular position is widely applied to modern equipment, the technical scheme is mainly realized by adopting a brush/brushless direct current torque motor and an angular position sensor, wherein the commonly used angular position sensor comprises a resolver, a grating code wheel, a potentiometer and a Hall sensor, the purchase price is different from hundreds to tens of thousands of yuan, and the cost expenditure of the control system is greatly increased. Therefore, it is necessary to design a servo control device with simple structure and low cost.
The stepping motor has the advantages of large torque, small inertia, high response frequency and the like, so the stepping motor has the excellent characteristics of instant starting and quick stopping. The output rotation angle or displacement precision is high, errors can not be accumulated, and the device is an ideal device used as a control system.
The closed-loop control technology based on the angular position is widely applied to modern equipment, the technical scheme is mainly realized by adopting a brush/brushless direct current torque motor and an angular position sensor, wherein the commonly used angular position sensor comprises a resolver, a grating code wheel, a potentiometer and a Hall sensor, the purchase price is different from hundreds to tens of thousands of yuan, and the cost expenditure of the control system is greatly increased.
Disclosure of Invention
The invention aims to provide a follow-up control device based on a stepping motor and a photoelectric switch, which is used for solving the defects of the prior art.
The invention relates to a servo control device based on a stepping motor and a photoelectric switch, which comprises a control circuit board, the stepping motor and the photoelectric switch; the core processor of the control circuit board is jointly completed by adopting a DSP and an FPGA; the FPGA includes: the stepping motor control module is used for converting a motor rotating speed value sent by the DSP into a pulse signal capable of controlling the stepping motor in real time, the rising edge of the pulse signal is effective, and the running step number of the motor is controlled by the number of pulses generated per second; the photoelectric switch signal filtering module is used for filtering input signals of the two photoelectric switches so as to eliminate interference; the angle counting and correcting module accumulates the rotating step number of the stepping motor, accumulates the rotating step number in the forward rotation process, decreases the rotating step number in the reverse rotation process, and corrects the current accumulated step number value through a photoelectric switch signal; after the DSP is electrified, the rotation of the whole motion range is executed, the zero position is searched, and the position of the zero position is recorded; DSPb) generates a speed value of the stepping motor through a PID algorithm according to the current angle value and the target position fed back by the FPGA, and sends the speed value to the FPGA.
According to an embodiment of the servo control device based on the stepping motor and the photoelectric switch, the stepping motor control module can set the working state of the stepping motor to enable, running direction and current selection, and simultaneously controls the rotating speed of the stepping motor through a speed instruction sent by the DSP.
An embodiment of the servo control device according to the invention based on a stepping motor and an electro-optical switch, wherein signals with a pulse level of less than 10us are considered as interference signals and are filtered out.
According to an embodiment of the servo control device based on the stepping motor and the photoelectric switch, when the two input signals have high and low level changes, the photoelectric switch signal filtering module respectively performs sampling counting processing for 10us, if opposite levels appear in 10us, the counter is cleared, and the signals are considered to be stable until the counter is full of 10 us.
According to an embodiment of the servo control device based on the stepping motor and the photoelectric switch, the angle counting of the angle counting and correcting module is realized by a counter, firstly, a signal is judged to determine the running direction of the motor, and the motor is accumulated or subtracted; the counter is added and subtracted by detecting the rising edge of the signal, the angle correction is realized by detecting the signal, and the counter is corrected.
According to an embodiment of the servo control device based on the stepping motor and the photoelectric switch, the stepping motor is a two-phase stepping motor.
According to an embodiment of the servo control device based on the stepping motor and the photoelectric switch, 2 photoelectric switches are arranged on the motor side, the 2 photoelectric switches are matched with the baffle plates for use, and the baffle plates and the photoelectric switch are combined to realize the cut-in and cut-out response at the positions of-4 degrees, +4 degrees, -22 degrees and +22 degrees.
The servo control device overcomes the defects of the prior art, and develops the servo control device based on the stepping motor and the photoelectric switch, the device can realize a traditional position closed-loop control system, has an angle correction function, and errors cannot be accumulated. The controller consists of a control circuit, 1 stepping motor and 2 photoelectric switches, can realize closed-loop control based on an angular position, has low cost and has wide application prospect in occasions with low control precision requirements.
Drawings
FIG. 1 is a schematic diagram of a servo control device based on a stepping motor and a photoelectric switch according to the present invention;
FIG. 2 is a diagram of the input/output interface of the control module of the stepping motor;
FIG. 3 is a diagram showing the relationship between the input and output interfaces of the signal filtering module of the photoelectric switch;
FIG. 4 is a diagram showing the relationship between the input and output interfaces of the angle counting and correction module;
FIG. 5 is a functional diagram of the optoelectronic switch;
fig. 6 is a schematic diagram illustrating the functional principle of the photoelectric switch.
Detailed Description
In order to make the objects, contents, and advantages of the present invention clearer, the following detailed description of the embodiments of the present invention will be made in conjunction with the accompanying drawings and examples.
Fig. 1 is a schematic diagram of a servo control device based on a stepping motor and a photoelectric switch, as shown in fig. 1, fig. 1 is a schematic diagram of a servo control device based on a stepping motor and a photoelectric switch, which includes a control circuit board, a stepping motor and a photoelectric switch.
As shown in fig. 1, a core processor of a control circuit board (1) is jointly completed by using a DSP and an FPGA, and a software program in the FPGA is composed of 3 functional modules:
a) and a stepping motor control module. The motor rotating speed value sent by the DSP is converted into a pulse signal capable of controlling the stepping motor in real time, the rising edge of the pulse signal is effective, and the number of the motor operation steps, namely the rotating speed, is controlled by the number of pulses generated per second.
The stepping motor control module can set the working state (enabling, running direction and current selection) of the stepping motor, and controls the rotating speed of the stepping motor through a speed instruction sent by the DSP, and the relation of the input and output interfaces of the module is shown in FIG. 2.
b) Photoelectric switch signal filtering module. The two photoelectric switch input signals are filtered to eliminate interference, and the signals with the pulse level less than 10us are considered as interference signals and are filtered.
As shown in fig. 3, when the high and low levels of two input signals of Collector1_ in and Collector2_ in change, 10us of sampling count processing is performed, if the opposite levels appear in 10us, the counter is cleared, and the signal is considered to be stable until the counter counts 10us, and the signal can be output.
c) And an angle counting and correcting module. The step number of the step motor is accumulated, the step number is accumulated in the forward rotation process and the step number is accumulated in the reverse rotation process, and the current accumulated step number is corrected through a photoelectric switch signal.
The relation of the input and output interfaces of the module is shown in fig. 4, the angle counting is realized by a counter, a Dir signal is judged to determine the running direction of the motor, the Dir signal is accumulated when the Dir is high, the Dir signal is accumulated when the Dir is low, and the counter CountStepNum is a 16-bit register; and adding and subtracting the counter by detecting the rising edge of the Step signal. The angle correction is realized by detecting two signals of COL1 and COL2, and when COL1 is at high level and COL2 has a rising edge, the counter CountStepNum is corrected to a value corresponding to-4 degrees; when COL2 is high and COL1 has a rising edge, the counter CountStepNum is corrected to a value corresponding to +4 °; when COL2 is low and COL1 has a falling edge, the counter CountStepNum is corrected to a value corresponding to-20 degrees; when COL1 is low and COL2 has a falling edge, the counter CountStepNum is corrected to a value corresponding to +20 °;
the DSP completes the main work as follows:
a) after power-on, the whole movement range is rotated, zero position is searched, and the position of the zero position is recorded;
b) and generating a speed value of the stepping motor through a PID algorithm according to the current angle value and the target position fed back by the FPGA, and sending the speed value to the FPGA.
The invention selects the FPGA to drive the stepping motor and receive the photoelectric switch signal without being directly executed by the DSP, because the control frequency of the DSP is a few KHz and the speed is slow, the receiving of the photoelectric switch signal is delayed greatly, thereby introducing errors, and the running period of the FPGA is tens of ns, thereby reducing the delay errors to the maximum extent.
(2) A stepper motor. The stepping motor is a commonly used two-phase stepping motor.
(3) A photoelectric switch. The number of the photoelectric switches is 2, the photoelectric switches are arranged on the side of the motor, HOA1872 of the Honeywell company is selected as the photoelectric switches, and the photoelectric switches have the characteristics of low cost, high response speed and high reliability. 2 photoelectric switches are matched with blocking pieces for use, the length coverage range of the blocking pieces is 26 degrees, particularly as shown in figure 5, the blocking pieces and the photoelectric switches are combined to realize the cut-in and cut-out response at the positions of-4 degrees, +4 degrees, -22 degrees and +22 degrees, the principle is shown in figure 6, wherein '00', '10', '11', '01' and '00' represent the switching states of the two photoelectric switches, are shielded by the blocking pieces to be '1', and are not shielded to be '0'; the +/-4-degree two positions are used for angle correction, namely the FPGA corrects the accumulated angle value to +/-4 degrees when the stepping motor passes the +/-4-degree photoelectric switch position; and two positions of +/-22 degrees are used for limiting protection. The above description realizes the position range of-22 deg., and can also realize any angle range by modifying the length of the blocking piece of the photoelectric switch.
Compared with the prior art, the invention has the beneficial effects that:
(1) the servo control system does not need a position sensor as a feedback device, so that the cost is greatly reduced;
(2) the structure is simpler and more compact because a position sensor is omitted;
(3) the angle correction is carried out when the angle passes through the-4-degree position and the + 4-degree position in the movement range, so that the accuracy of the long-time operation position is ensured.
The photoelectric switch as a photoelectric device has the advantages of small volume, high positioning precision and low cost, and is commonly used for limiting or zero searching. The invention is a follow-up control device with simple structure and low cost.
The above description is only a preferred embodiment of the present invention, and it should be noted that, for those skilled in the art, several modifications and variations can be made without departing from the technical principle of the present invention, and these modifications and variations should also be regarded as the protection scope of the present invention.
Claims (7)
1. A follow-up control device based on a stepping motor and a photoelectric switch is characterized by comprising a control circuit board, the stepping motor and the photoelectric switch;
the core processor of the control circuit board is jointly completed by adopting a DSP and an FPGA;
the FPGA includes: the stepping motor control module is used for converting a motor rotating speed value sent by the DSP into a pulse signal capable of controlling the stepping motor in real time, the rising edge of the pulse signal is effective, and the running step number of the motor is controlled by the number of pulses generated per second; the photoelectric switch signal filtering module is used for filtering input signals of the two photoelectric switches so as to eliminate interference; the angle counting and correcting module accumulates the rotating step number of the stepping motor, accumulates the rotating step number in the forward rotation process, decreases the rotating step number in the reverse rotation process, and corrects the current accumulated step number value through a photoelectric switch signal;
after the DSP is electrified, the rotation of the whole motion range is executed, the zero position is searched, and the position of the zero position is recorded; DSPb) generates a speed value of the stepping motor through a PID algorithm according to the current angle value and the target position fed back by the FPGA, and sends the speed value to the FPGA.
2. The stepping motor and electro-optical switch based servo control device according to claim 1, wherein the stepping motor control module is capable of setting the operating states of the stepping motor to enable, running direction and current selection, and controlling the rotating speed of the stepping motor through a speed command issued by the DSP.
3. A stepper motor and electro-optical switch based servo control as claimed in claim 1 wherein signals with pulse levels less than 10us are filtered out as interfering signals.
4. The servo control device based on the stepping motor and the photoelectric switch as claimed in claim 1, wherein the photoelectric switch signal filtering module performs sampling counting processing for 10us when the two input signals have high and low level changes, if the opposite level appears in 10us, the counter is cleared, and the signal is considered to be stable until the counter is full of 10 us.
5. The stepping motor and photoelectric switch based servo control device according to claim 1, wherein the angle counting of the angle counting and correcting module is realized by a counter, and the judgment signal determines the running direction of the motor, and is accumulated or subtracted; the counter is added and subtracted by detecting the rising edge of the signal, the angle correction is realized by detecting the signal, and the counter is corrected.
6. The stepping motor and electro-optical switch based servo control device according to claim 1, wherein the stepping motor is a two-phase stepping motor.
7. A stepping motor and opto-electronic switch based servo control as claimed in claim 1 wherein the opto-electronic switches are 2 in number and are mounted on the motor side, and wherein the 2 opto-electronic switches are used in combination with a shutter which in combination with the opto-electronic switches enables the switching in and out responses at the-4 °, +4 °, -22 °, and +22 °.
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